Disc drive machines record and reproduce information on a recording media. The media generally takes the form of circular information storage discs having a multiplicity of concentric tracks. Conventional Winchester type disc drives include a disc pack holding a plurality of vertically aligned rotating information storage discs, each having at least one associated magnetic head that is adapted to transfer information between the disc and an external system. Each head is carried by an elongated flexure arm. The flexure arms are vertically aligned and are each attached to a common head positioner assembly. The head positioner assembly may be either rotationally mounted, or may take the form of a linear carriage that is free to move back and forth along a single axis. In rotary mounted head positioner assemblies, a voice coil motor rotates the head positioner assembly about a pivot mechanism to precisely position the heads relative to the magnetic discs.
The housing is typically divided into upper and lower casings which are sealed together with a gasket to prevent the introduction of dirty air into the disc drive. The gasket also serves to dampen vibrations within the housing.
As will be appreciated by those skilled in the art, it is extremely important to the operation of the disc drive to maintain a dust free environment within the drive. To prevent dust particles from entering into the drive in the first place it is important to thoroughly filter any air that enters the drive from the outside. Traditionally drives are vented to the outside only through a breather filter that very efficiently filters dust particles from any air passing therethrough. However, since leaks do occasionally occur, it is desirable to operate the drive at pressures slightly above atmospheric pressures so that any leakage flows out of the drive as opposed to into the drive.
The principle source of dust within the drive is microparticles that flake off of the magnetic discs 20 by contact with the heads when the drive is started and stopped. Other parts that rub during operation can cause dust particles as well. Therefore, it is necessary to provide some internal filtering as well. Conventional filter systems tend to require bulky filtration systems that often are difficult to assemble and/or get in way during repair operations.